Target-mediated self-assembly of DNA networks for sensitive detection and intracellular imaging of APE1 in living cells.

Herein, giant DNA networks were assembled from two kinds of functionalized tetrahedral DNA nanostructures (f-TDNs) for sensitive detection and intracellular imaging of apurinic/apyrimidinic endonuclease 1 (APE1) as well as gene therapy in tumor cells. Impressively, the reaction rate of the catalytic hairpin assembly (CHA) reaction on f-TDNs was much faster than that of the conventional free CHA reaction owing to the high local concentration of hairpins, spatial confinement effect and production of giant DNA networks, which significantly enhanced the fluorescence signal to achieve sensitive detection of APE1 with a limit of 3.34 × 10 U μL.

A hierarchical integrated 3D carbon electrode derived from gingko leaves hydrothermal carbonization of HPO for high-performance supercapacitors.

Electrochemical ultracapacitors derived from green and sustainable materials could demonstrate superior energy output and an ultra-long cycle life owing to large accessible surface area and obviously shortened ion diffusion pathways. Herein, we have established an efficient strategy to fabricate porous carbon (GLAC) from sustainable gingko leaf precursors by a facile hydrothermal activation of HPO and low-cost pyrolysis. In this way, GLAC with a hierarchically porous structure exhibits extraordinary adaptability toward a high energy/power supercapacitor (∼709 F g at 1 A g) in an aqueous electrolyte (1 M KOH).

[Two new triterpeneoids from roots of Dolomiaea souliei].

The present study analyzed the chemical constituents in dried roots of Dolomiaea souliei. Chromatographic methods, such as normal-phase, and reversed-phase column chromatography, TLC, and preparative HPLC, were applied to separate and purify the petroleum ether extract of D. souliei.

Programmable mismatch-fueled high-efficiency DNA signal amplifier.

Herein, by introducing mismatches, a high-efficiency mismatch-fueled catalytic multiple-arm DNA junction assembly (M-CMDJA) with high-reactivity and a high-threshold is developed as a programmable DNA signal amplifier for rapid detection and ultrasensitive intracellular imaging of miRNA. Compared with traditional nucleic acid signal amplification (NASA) with a perfect complement, the M-CMDJA possesses larger kinetic and thermodynamic favorability owing to the more negative reaction standard free energy (Δ) as driving force, resulting in much higher efficiency and rates. Once traces of the input initiator react with the mismatched substrate DNA, it could be converted into amounts of output multiple-arm DNA junctions the M-CMDJA as the functional DNA conversion nanodevice.

Electronic structure, magnetoresistance and spin filtering in graphene|2 monolayer-CrI3|graphene van der Waals magnetic tunnel junctions.

In the pursuit of designing van der Waals magnetic tunneling junctions (vdW-MTJs) with two-dimensional (2D) intrinsic magnets, as well as to quantitatively reveal the microscopic nature governing the vertical tunneling pathways beyond the phenomenological descriptions on CrI-based vdW-MTJs, we investigate the structural configuration, electronic structure and spin-polarized quantum transport of graphene|2 monolayer(2ML)-CrI|graphene heterostructure with Ag(111) layers as the electrode, using density functional theory (DFT) and its combination of non-equilibrium Green's function (DFT-NEGF) methods. The in-plane lattice of CrI layers is found to be stretched when placed on the graphene (Gr) layer, and the layer-stacking does not show any site selectivity. The charge transfer between CrI and Gr layers make the CrI layer lightly electron-doped, and the Gr layer hole-doped.

A stimulus-responsive hexahedron DNA framework facilitates targeted and direct delivery of native anticancer proteins into cancer cells.

The targeted and direct intracellular delivery of proteins plays critical roles in biological research and disease treatments, yet remains highly challenging. Current solutions to such a challenge are limited by the modification of proteins that may potentially alter protein functions inside cells or the lack of targeting capability. Herein, we develop a stimulus-responsive and bivalent aptamer hexahedron DNA framework (HDF) for the targeted and direct delivery of native therapeutic proteins into cancer cells.

Enhanced antibacterial activity with increasing P doping ratio in CQDs.

It is an urgent challenge to develop efficient antibacterial agents against resistant bacteria in the treatment of infectious diseases. Carbon quantum dots (CQDs) have attracted much attention owing to their good stability, low toxicity and excellent biocompatibility. In this work, CQDs doped with different contents of the element phosphorus (P) were prepared by a simple hydrothermal method using valine as a carbon source, triethylamine as a nitrogen source and different volumes of phosphoric acid as a phosphorus source.

Bio-inspired hierarchical nanoporous carbon derived from water spinach for high-performance supercapacitor electrode materials.

Due to various properties, green carbon nanomaterials with high specific surface area and environmentally friendly features have aroused extensive interest in energy storage device applications. Here, we report a facile, one-step carbonization of water spinach to synthesize porous carbon that exhibits a high specific surface area of ∼1559 m g, high specific capacitance (∼1191 F g at 1 A g), a low intercept (0.9 Ω), outstanding rate capability and superior cycling stability (94.

Molecular mechanisms of the antibacterial activity of polyimide fibers in a skin-wound model with Gram-positive and Gram-negative bacterial infection .

Recently, the need for antibacterial dressings has amplified because of the increase of traumatic injuries. However, there is still a lack of ideal, natural antibacterial dressings that show an efficient antibacterial property with no toxicity. Polyimide (PI) used as an implantable and flexible material has been recently reported as a mixture of particles showing more desirable antibacterial properties.

Highly luminescent and stable quasi-2D perovskite quantum dots by introducing large organic cations.

Herein, ultra-stable quasi-two-dimensional perovskite quantum dots (quasi-2D PQDs) are synthesized by introducing the butylamine cation (BA) into the methylamine lead bromide perovskite (MAPbBr). By reducing the dimensionality of the perovskite structure, the quasi-2D perovskite (BA)(MA) Pb Br presents higher luminescence efficiency and better environmental stability than traditional 3D perovskites, which is mainly because the dimensionality-reduced perovskite has higher exciton binding energy and formation energy. Under an optimal MA : BA ratio of 1 : 1, the quasi-2D perovskite exhibits about four times higher luminescence efficiency (PLQY = 49.

Nitrogen defect-containing polymeric carbon nitride for efficient photocatalytic H evolution and RhB degradation under visible light irradiation.

Introducing defects in polymeric carbon nitride (CN) in a predetermined way is a great challenge to explicate the effect of defects on the photocatalytic activity. Herein, we provide a pathway to synthesize g-CN with nitrogen defects by simply calcining melamine and trithiocyanuric acid at elevated temperature. Nitrogen defects at the N-bridging sites lead to an intermediate energy gap between the valence band and the conduction band, which greatly increases the photon absorption in the visible light range.

Erratum: Lycorine hydrochloride inhibits melanoma cell proliferation, migration and invasion via down-regulating p21.

[This corrects the article on p. 1391 in vol. 11, PMID: 33948364.

Biocatalytic cascades and intercommunicated biocatalytic cascades in microcapsule systems.

Biomolecule-loaded nucleic acid-functionalized carboxymethyl cellulose hydrogel-stabilized microcapsules (diameter 2 μm) are introduced as cell-like containments. The microcapsules are loaded with two DNA tetrahedra, T and T, functionalized with guanosine-rich G-quadruplex subunits, and/or with native enzymes (glucose oxidase, GOx, and/or β-galactosidase, β-gal). In the presence of K-ions and hemin, the T/T tetrahedra constituents, loaded in the microcapsules, assemble into a hemin/G-quadruplex bridged tetrahedra dimer DNAzyme catalyzing the oxidation of Amplex Red to Resorufin by generating HO.

Iminyl radical-triggered relay annulation for the construction of bridged aza-tetracycles bearing four contiguous stereogenic centers.

Bridged tetracyclic nitrogen scaffolds are found in numerous biologically active molecules and medicinally relevant structures. Traditional methods usually require tedious reaction steps, and/or the use of structurally specific starting materials. We report an unprecedented, iminyl radical-triggered relay annulation from oxime-derived peresters and azadienes, which shows good substrate scope and functional group compatibility, and can deliver various bridged aza-tetracyclic compounds with complex molecular topology and four contiguous stereogenic centers (dr > 19 : 1) in a single operation.

Rational design of M-N-Gr/VC heterostructures as highly active ORR catalysts: a density functional theory study.

Inspired by the composites of N-doped graphene and transition metal-based materials as well as MXene-based materials, heterostructures (M-N-Gr/VC) of eight different transition metals (M = Ti, Cr, Mn, Fe, Co, Ni, Cu, and Zn) doped with nitrogen-coordinated graphene and VC as potential catalysts for the oxygen reduction reaction (ORR) using density functional theory (DFT) were designed and are described herein. The calculations showed that the heterostructure catalysts (except for Zn-N-Gr/VC) were thermodynamically stable. Ni-N-Gr/VC and Co-N-Gr/VC showed higher activities towards the ORR, with overpotentials as low as 0.

Correction: Cationic conjugated polymer-based FRET aptasensor for label-free and ultrasensitive ractopamine detection.

[This corrects the article DOI: 10.1039/D2RA00574C.].

Ferritin-catalyzed synthesis of ferrihydrite nanoparticles with high mimetic peroxidase activity for biomolecule detection.

Natural enzymes are generally sophisticated structural proteins that catalyze biological reactions with high specificity and efficiency and thus offer great potential in various disciplines, but intrinsic proteinic features such as easy denaturation and digestion restrict their practical application. So far, many functional nanomaterials with robust structures have been advanced as enzyme-mimetic catalysts to replace natural enzymes, however, their synthesis processes are generally complicated and require harsh experimental conditions such as high temperature and pressure. Herein, we report the facile synthesis of nanoparticles with high peroxidase-like activity by enzymatic catalysis.

The crystal structures, phase stabilities, electronic structures and bonding features of iridium borides from first-principles calculations.

We present results of an unbiased structure search for the lowest energy crystalline structures of various stoichiometric iridium borides, using first-principles calculations combined with particle swarm optimization algorithms. As a result, besides three stable phases of 2/-IrB, 2-IrB, and -IrB, three promising metastable phases, namely, 2/-IrB, 2/-IrB, and -IrB, whose energies are within 20 meV per atom above the convex hull curve, are also identified at ambient pressure. The high bulk modulus of 301 GPa, highest shear modulus of 148 GPa, and smallest Poisson's ratio of 0.

Enantioselective synthesis of α-amino ketones through palladium-catalyzed asymmetric arylation of α-keto imines.

Chiral α-amino ketones are common structural motifs in natural products and pharmaceuticals, as well as important synthons in organic synthesis. Thus, establishing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein we disclose a new catalytic asymmetric approach for the synthesis of chiral α-amino ketones through a chiral palladium-catalyzed arylation reaction of generated challenging α-keto imines from previously unreported -acyl -sulfonyl-,-aminals, with arylboronic acids.

Exploration of conjugated π-bridge units in ,-bis(4-methoxyphenyl)naphthalen-2-amine derivative-based hole transporting materials for perovskite solar cell applications: a DFT and experimental investigation.

Organic small molecules as hole-transporting materials (HTMs) are an important part of perovskite solar cells (PSCs). On basis of the arylamine-based HTM ( H101), two ,-bis(4-methoxyphenyl)naphthalen-2-amine derivative-based HTMs (CP1 and CP2) with different conjugated π-bridge cores of fused aromatic ring are designed. The CP1 and CP2 were investigated by DFT and TD-DFT in combination with Marcus theory.

Cationic conjugated polymer-based FRET aptasensor for label-free and ultrasensitive ractopamine detection.

A label-free fluorescence resonance energy transfer (FRET) platform based on cationic conjugated polymers and aptamers for ultrasensitive and specific ractopamine detection was constructed. This method exhibited a wide linear range from 0.05 to 500 μM and a low limit of detection of 47 nM, which make it an attractive assay platform for foodborne doping.

A study on hydrogen storage performance of Ti decorated vacancies graphene structure on the first principle.

The structural properties, formation energy, adsorption energy, and electronic properties of vacancy graphene are studied by first-principles analysis. We found that the formation energy and adsorption energy of double vacancy graphene (DVG-4) are the largest. A single defect in DVG-4 can adsorb at least nine hydrogen molecules, and compared with Ti modified single vacancy graphene (SVG-Ti), the adsorption capacity is increased by 80%.

[Chemical constituents of cyclic peptides from fibrous roots of Pseudostellaria heterophylla].

Four cyclic peptides were isolated from the 75% ethanol extract of the fibrous roots of Pseudostellaria heterophylla by silica gel, Sephadex LH-20 column chromatography, and semi-preparative HPLC. Through mass spectrometry, NMR and other methods, they were identified as pseudostellarin L(1), heterophyllin B(2), pseudostellarin B(3), and pseudostellarin C(4). Among them, compound 1 was a new cyclic peptide, and compounds 2-4 were isolated from the fibrous roots of P.

A coordination cage hosting ultrafine and highly catalytically active gold nanoparticles.

Ultrafine metal nanoparticles (MNPs) with size <2 nm are of great interest due to their superior catalytic capabilities. Herein, we report the size-controlled synthesis of gold nanoparticles (Au NPs) by using a thiacalixarene-based coordination cage CIAC-108 as a confined host or stabilizer. The Au NPs encapsulated within the cavity of CIAC-108 (Au@CIAC-108) show smaller size (∼1.

A core-brush 3D DNA nanostructure: the next generation of DNA nanomachine for ultrasensitive sensing and imaging of intracellular microRNA with rapid kinetics.

A highly loaded and integrated core-brush three-dimensional (3D) DNA nanostructure is constructed by programmatically assembling a locked DNA walking arm (DA) and hairpin substrate (HS) into a repetitive array along a well-designed DNA track generated by rolling circle amplification (RCA) and is applied as a 3D DNA nanomachine for rapid and sensitive intracellular microRNA (miRNA) imaging and sensing. Impressively, the homogeneous distribution of the DA and HS at a ratio of 1 : 3 on the DNA track provides a specific walking range for the DA to avoid invalid and random self-walking and notably improve the executive ability of the core-brush 3D DNA nanomachine, which easily solves the major technical challenges of traditional Au-based 3D DNA nanomachines: low loading capacity and low executive efficiency. As a proof of concept, the interaction of miRNA with the 3D DNA nanomachine could initiate the autonomous and progressive operation of the DA to cleave the HS for ultrasensitive ECL detection of target miRNA-21 with a detection limit as low as 3.